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author | Ben Hutchings <bhutchings@solarflare.com> | 2011-06-24 20:26:44 +0100 |
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committer | Ben Hutchings <bhutchings@solarflare.com> | 2011-06-25 00:43:48 +0100 |
commit | 4017dbdc14af1903dc9fcba4d08b89c02325069d (patch) | |
tree | 33c61638e1fb98ebf27f710e99f443aed9c2f738 | |
parent | 22c8c9343258feda9ea9ebb9e5f8cbb727b69454 (diff) | |
download | linux-3.10-4017dbdc14af1903dc9fcba4d08b89c02325069d.tar.gz linux-3.10-4017dbdc14af1903dc9fcba4d08b89c02325069d.tar.bz2 linux-3.10-4017dbdc14af1903dc9fcba4d08b89c02325069d.zip |
sfc: Fix loop condition for efx_filter_search() when !for_insert
efx_filter_remove_filter() fails to remove inserted filters in some cases.
For example:
1. Two filters A and B have specifications that result in an initial
hash collision.
2. A is inserted first, followed by B.
3. An attempt to remove B first succeeds, but if A is removed first
a subsequent attempt to remove B fails.
When searching for an existing filter (!for_insert),
efx_filter_search() must always continue to the maximum search depth
for the given type rather than stopping at the first unused entry.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
-rw-r--r-- | drivers/net/sfc/filter.c | 41 |
1 files changed, 24 insertions, 17 deletions
diff --git a/drivers/net/sfc/filter.c b/drivers/net/sfc/filter.c index f2fc2587c09..054f0a3d45a 100644 --- a/drivers/net/sfc/filter.c +++ b/drivers/net/sfc/filter.c @@ -335,28 +335,35 @@ static int efx_filter_search(struct efx_filter_table *table, bool for_insert, int *depth_required) { unsigned hash, incr, filter_idx, depth, depth_max; - struct efx_filter_spec *cmp; hash = efx_filter_hash(key); incr = efx_filter_increment(key); - depth_max = (spec->priority <= EFX_FILTER_PRI_HINT ? - FILTER_CTL_SRCH_HINT_MAX : FILTER_CTL_SRCH_MAX); - - for (depth = 1, filter_idx = hash & (table->size - 1); - depth <= depth_max && test_bit(filter_idx, table->used_bitmap); - ++depth) { - cmp = &table->spec[filter_idx]; - if (efx_filter_equal(spec, cmp)) - goto found; + + filter_idx = hash & (table->size - 1); + depth = 1; + depth_max = (for_insert ? + (spec->priority <= EFX_FILTER_PRI_HINT ? + FILTER_CTL_SRCH_HINT_MAX : FILTER_CTL_SRCH_MAX) : + table->search_depth[spec->type]); + + for (;;) { + /* Return success if entry is used and matches this spec + * or entry is unused and we are trying to insert. + */ + if (test_bit(filter_idx, table->used_bitmap) ? + efx_filter_equal(spec, &table->spec[filter_idx]) : + for_insert) { + *depth_required = depth; + return filter_idx; + } + + /* Return failure if we reached the maximum search depth */ + if (depth == depth_max) + return for_insert ? -EBUSY : -ENOENT; + filter_idx = (filter_idx + incr) & (table->size - 1); + ++depth; } - if (!for_insert) - return -ENOENT; - if (depth > depth_max) - return -EBUSY; -found: - *depth_required = depth; - return filter_idx; } /* Construct/deconstruct external filter IDs */ |